"Swoozie Pellegrino" wrote in message
...
On Feb 11, 10:41 pm, Rick Frazier wrote:
Swoozie Pellegrino wrote:
Hi, all.

I'm about to become a General class licensee, and I'm
trying to work out a HF antenna plan for my new apartment.
I have a small balcony on the top (4th) floor, which is good,
but unfortunately there's a roof overhanging it and is
8' over the balcony floor and juts 4' out over the balcony edge,
so a tall vertical is out of the question.

What about a 'vertical' that is angled about 45 deg. down
from vertical? Will that be good for phone DXing on any
HF band?

Also, sadly, the balcony is all metal and so is the top of
the roof.

What about some kind of loop?

Thanks!

~swooz

How about a vertical suspended from a hunk of plastic pipe ? Try
letting it hang down from the balcony, as far out as you can safely
suspend it. I've gotten away with using a 24 guage wire suspended with
a collapsable/extendible fishing pole with reasonable results, compared
to trying to use a short dipole inside a hotel room....

Though far from optimum, sometimes almost anything is better than nothing.

--Rick AH7H- Hide quoted text -

- Show quoted text -

I could fashion a 24 gauge 1/2-wavelength 20m dipole, which I know
about its footprint when strung horizontally at 1/2-wavelength above
the ground, but is it of any use stood on end (as in dangled from
my balcony and tapped in the center)?

Thanks,
~swooz

Sure is -- tis a vertical dipole - works well at low heights where a
horizontal dipole should be elevated above ground - half wavelength +

Be sure to center tap it for proper impedance match. Not end fed.

Feedline should be 90 deg from the dipole or as near as you can get it.

I use a vertical dipole on six meters - works well

Lamont

On Feb 13, 11:11*am, "The Shadow" wrote:
"Swoozie Pellegrino" wrote in message

...
On Feb 11, 10:41 pm, Rick Frazier wrote:





Swoozie Pellegrino wrote:
Hi, all.

I'm about to become a General class licensee, and I'm
trying to work out a HF antenna plan for my new apartment.
I have a small balcony on the top (4th) floor, which is good,
but unfortunately there's a roof overhanging it and is
8' over the balcony floor and juts 4' out over the balcony edge,
so a tall vertical is out of the question.

What about a 'vertical' that is angled about 45 deg. down
from vertical? Will that be good for phone DXing on any
HF band?

Also, sadly, the balcony is all metal and so is the top of
the roof.

What about some kind of loop?

Thanks!

~swooz

How about a vertical suspended from a hunk of plastic pipe ? Try
letting it hang down from the balcony, as far out as you can safely
suspend it. I've gotten away with using a 24 guage wire suspended with
a collapsable/extendible fishing pole with reasonable results, compared
to trying to use a short dipole inside a hotel room....

Though far from optimum, sometimes almost anything is better than nothing.

--Rick AH7H- Hide quoted text -

- Show quoted text -

I could fashion a 24 gauge 1/2-wavelength 20m dipole, which I know
about its footprint when strung horizontally at 1/2-wavelength above
the ground, but is it of any use stood on end (as in dangled from
my balcony and tapped in the center)?

Thanks,
~swooz

Sure is -- tis a vertical dipole - works well at low heights where a
horizontal dipole should be elevated above ground - half wavelength +

Be sure to center tap it for proper impedance match. Not end fed.

Feedline should be 90 deg from the dipole or as near as you can get it.

I use a vertical dipole on six meters - works well

Lamont- Hide quoted text -

- Show quoted text -

Thanks for the info, Lamont. Well, it's going to be difficult to get
that
90 deg angle at the central feed point, since the 'dipole' will be
something
like a 10-meter long magnet wire hanging from my balcony with a weight
at the bottom. I could run coax down alongside for 5m and have it
connect
there in the center.

Hmmm...wonder if a Buddipole clamped on my balcony railing and
pointed out at a 45 deg angle will work better for me.

Thanks,
~swooz

On Thu, 14 Feb 2008 08:44:40 -0800 (PST), Swoozie Pellegrino
wrote:

like a 10-meter long magnet wire hanging from my balcony with a weight
at the bottom. I could run coax down alongside for 5m and have it
connect
there in the center.

Make it 5 meter long wire hanging from the center conductor of a
hanging 5+ meter long coax.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
Swoozie Pellegrino wrote:

like a 10-meter long magnet wire hanging from my balcony with a weight
at the bottom. I could run coax down alongside for 5m and have it
connect there in the center.

Make it 5 meter long wire hanging from the center conductor of a
hanging 5+ meter long coax.

Or fold 1/4WL of the braid back down over itself leaving
1/4WL of the insulated center conductor to hang down.
It's called a sleeve dipole.
--
73, Cecil http://www.w5dxp.com

On Feb 14, 3:22*pm, Cecil Moore wrote:
Richard Clark wrote:
Swoozie Pellegrino wrote:

like a 10-meter long magnet wire hanging from my balcony with a weight
at the bottom. *I could run coax down alongside for 5m and have it
connect there in the center.

Make it 5 meter long wire hanging from the center conductor of a
hanging 5+ meter long coax.

Or fold 1/4WL of the braid back down over itself leaving
1/4WL of the insulated center conductor to hang down.
It's called a sleeve dipole.
--
73, Cecil *http://www.w5dxp.com

What might the impedance of this look like, say, if I
took the last 10 meters of a 100' 50-ohm coax piece
and slice it to split out into a 20-meter sleeve dipole
and hung the dipole part vertically from the balcony?
Can I just screw the other end onto the back of
my transceiver and go? Or....


Thanks,
~swooz

On Fri, 15 Feb 2008 11:40:50 -0800 (PST), Swoozie Pellegrino
wrote:

What might the impedance of this look like, say, if I
took the last 10 meters of a 100' 50-ohm coax piece
and slice it to split out into a 20-meter sleeve dipole
and hung the dipole part vertically from the balcony?
Can I just screw the other end onto the back of
my transceiver and go? Or....

Sure, if you can live with the mismatch. Better if you can tune it
for one band. Or simply stick with my suggestion and run it into a
tuner which you will probably need anyway. The difference between any
of these will be undetectable at the far end of the QSO.

To reduce the chance of a hot chassis due to common mode currents, you
should use a 1:1 W2DU style BalUn (aka choke).

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Fri, 15 Feb 2008 11:40:50 -0800 (PST), Swoozie Pellegrino
wrote:

What might the impedance of this look like, say, if I
took the last 10 meters of a 100' 50-ohm coax piece
and slice it to split out into a 20-meter sleeve dipole
and hung the dipole part vertically from the balcony?
Can I just screw the other end onto the back of
my transceiver and go? Or....

Sure, if you can live with the mismatch. Better if you can tune it
for one band. Or simply stick with my suggestion and run it into a
tuner which you will probably need anyway. The difference between any
of these will be undetectable at the far end of the QSO.

To reduce the chance of a hot chassis due to common mode currents, you
should use a 1:1 W2DU style BalUn (aka choke).

73's
Richard Clark, KB7QHC

I've found that the trick of folding the braid down over the coax does a
very poor job of decoupling the line in an imitation of a "sleeve" or
"bazooka" dipole. It turns out that you really need a high Z0 for the
decoupling sleeve, and the only practical way I know of to do that is
with a larger diameter pipe, and air insulation between the pipe and the
coax. I've also found that a choke balun made of multiple turns on a
single core, by itself, anyway, doesn't provide adequate impedance. I'd
worry that a W2DU style balun would cause a lot of loss in this
application, but it should be possible to model it reasonably well with
a series of loads and find out. (You'd first need to determine the
actual Z of the type of core used, at the operating frequency.) You
might be able to decouple the line adequately with a very high impedance
and low resistance resonant current balun (common mode choke), perhaps
one made by winding coax on a plastic pop bottle. You'd probably need a
second current balun of some type about 1/4 wavelength down the line. My
experience is that it's a trickier problem than most people think.

Roy Lewallen, W7EL

Swoozie Pellegrino wrote:
What might the impedance of this look like, say, if I
took the last 10 meters of a 100' 50-ohm coax piece
and slice it to split out into a 20-meter sleeve dipole
and hung the dipole part vertically from the balcony?
Can I just screw the other end onto the back of
my transceiver and go? Or....

When I plugged it into a 2x6146 transceiver equipped
with a pi-net matching output network, it worked well. :-)
I would guess the SWR will be less than 2:1.
--
73, Cecil http://www.w5dxp.com